SllurUS. GANGETIC FISHES. 149 



lip, is tubular ; the hinder one is oblong, and in the middle be- 

 tween the eye and jaw. The eyes are small, and high. Each 

 of the gill-covers consists of one plate, very sharp behind. Its 

 membrane is fully exposed on the throat, but is so thick, that its 

 rays, if it contains any, are not visible. Under the lower jaw 

 is a slit. 



The sternum is exposed to view, and is striated with converg- 

 ing lines. The lateral line passes straight along the middle of 

 the side, but is faint. The vent is far forward. The tail forms 

 a sharp ridge above and below. 



The back fin is rounded at the end, and contains seven rays, 

 of which the first is simple, but not a prickle : the others are 

 branched. The pectoral fins are low and blunt, but longest 

 above : each contains eight rays, of which the first is a strong 

 sharp prickle, indented on both edges with barbs pointing 

 downward. The ventral fins are small, approach near each 

 other, and each contains six branched rays. The fin behind the 

 vent reaches close to that of the tail, but is not united to it, and, 

 forming a slight arch with its edge, contains about sixty-one 

 rays ; but the skin is so thick, that the number of rays cannot 

 be satisfactorily ascertained. The fin of the tail is rounded, 

 turned obliquely downward, and contains about twelve rays, be- 

 sides some short ones at each side. 



Subgenus. — Silurus callichrous. 

 The following five species for this tribe of fishes are rather 

 handsome, and have little or nothing of that lurid appearance 

 by which many kindred species are distinguished. They are 

 all very rich fine-flavoured food, and grow to from nine to 

 twelve inches in length. As they all have the strongest resem- 

 blance to each other, I shall content myself with describing the 

 first species only at length, and shall afterwards point out the 



